Driving gear for internal combustion engine-air compressor with double pistons



July 23, 1957 H. w. PETERsEN 2,800,270

A DRIVING GEAR FOR INTERNAL cOuBUsTION ENGINE-AIR COMPRESSOR WITH DOUBLE PIsTONs Filed March 29, 1952 .lll/1111111.21111'.wllllllllralllpl/llllllll ffm' m m w Eymsm 917m Amir.

DRIVING GEAR FoR INTERNAL coMBUsTIoN ingeglqlg-Anr coMPREssoR wrm DOUBLE Hans Christian Waldemar Petersen, Munich, Germany Application March 29, 1952, Serial No. `279,492.

8 Claims. (Cl. 230-56) v the pistons or plungers operate in opposite directions not only with respect to a center plane between and parallel to the two cylinder axes but also with respect to a plane at right angles to the axes of the cylinders. Various means have been'tried to ensure such desiredl movement of the pistons or plungers. However, the conventional devices either do not accomplish a permanent connection of the movable parts, thus causing a knocking each time the stroke changes its direction, and consequently causing undue wear and even break-downs, or the conventional devices for the indicated purpose are so heavy that the machine provided therewith cannot be operated with the high speed desired for internal combustion engines.

The present invention aims to avoid the mentioned drawbacks and to provide a drive for a machine of the mentioned type wherein the synchronization of the movement of the pistons or plungers is positively ensured by means permitting a high speed of operation.

Another object of the invention is the provision of a I machine of the mentioned typewherein each piston or plunger of the pair operating in one of the cylinders is connected by means of a rocking lever and piston rods to one piston or plunger ofthe pair operating in the other cylinder, and wherein both said levers journaled Yin the machine casing are connected by means positively ensuring oscillations of the levers in opposite directions.

Another object of the invention is the provision of a machine wherein the afore-mentioned rocking levers are journaled or pivoted in the center plane between the axes of the two cylinders and a synchronizing rod is so linked to the rocking levers eccentrically with respect to their pivots that the movement of the pistons and plungers in opposite directions is ensured and that all the pistons or plungers reach their dead center positions at the same time.

Further ,objects and details of the invention will be apparent from the description given hereinafter and the accompanying drawing illustrating an embodiment thereof by way of example.

In the drawing, Y

Fig. 1 is a diagrammatical longitudinal cross-section of a machine with a gear according to the invention,

Fig. 2 is a diagrammatical cross-section similar to Fig. 1 of a modification, and

Fig. 3 is an elevation partly in section of a modified part of the device illustrated in Fig. 1.

Referring now to the drawing in Fig. 1 my invention is shown as applied toa machine having two parallel jnited States Patent Cil ICC

` to render at least one part of the machine useful as a prime mover and at least one other part useful as an air compressor all such ancillary elements not effected by the invention have beenomitted in order to avoid overcrowding of the drawing.

In Fig. 1 the machine housing is denoted in general by 1. Interiorly of the housing, two cylinders 2 and 3 are formedV which are parallel to and spaced from each other. Cylinder 2 is provided with end extensions 4` and 5 of enlarged inner diameter, and cylinder 3 has similar end extensions 6 and 7. The cylinders 1 and 2 are shown as alike as to their shapey and dimensions and are arranged symmetrical with respect to a centerplane indi cated by the line a-a which is parallel to the .axes b-b and` c--c of the cylinders 2 and 3 respectively. The cylinders lare also symmetrical with respect to a plane indicated by line d-d and which is at right angles to the axes b-b and c-c.

Within cylinder 2, two hollow plungers 8 and 9 are reciprocable in the axial direction. In the illustrated embodiment each plunger is formed asA a stepped plunger in that plunger 8 includes an outer end portion 10 of an enlarged diameter movable in the cylinder extension 4, and `plunger 9 includes the outer portion 11 movable in the cylinder extension 5. In a similar manner two plungers 12 and 13 having stepped outer end portions 14 and `15 respectively are movable in cylinder 3 and extensions 6 and 7.

' In the lspecific arrangement of the drawing with stepped cylinders and pistons or plungers, cylinders 2 and 3 may be prime mover cylinders whereas the cylinder extensions 4 to 7 with plunger portions 10, 11, 14 and 15 respectively may serve as air compressors the output of which may be used at least in part, for scavenging and charging the prime mover cylinders.

According to the invention, a gear is provided in order to ensure synchronous movement of the plungers in opposite directions. For this purpose, a rocking lever 16 is journaled with its pivot pin 17 in the housing 1 so that the axis of the pin coincides with the plane ca -a. The end 18 of the one lever arm is linked to a piston rod 19 which is pivoted at 20 to plunger 8. The end 21 of the other lever arm is linked to rod 22 of plunger 12. An eccentric disc 23 is secured to or integral with the lever 16. In a similar manner another rocking lever 24 is journaled in the housing 1 at 25 in the same plane as lever 16. Its one arm end 26 is connected to plunger 9 via rod 27, `and its other arm end 28 to plunger 13 via the rod 29. The lever 24 is provided with an eccentric disc 30 similar to the disc 23. However, it is to be noted that the eccentricities of the discs are directed oppositely with respect to the line a-a, i. e. the eccentricities are arranged at with respect to each other when the levers are in their middle positions in which the connecting line of the centers of the arm ends 18 and 21, andthe connecting lineof the centers of the arm ends 26 and 28 are at right angles to the line a-a. Furthermore, it is to be noted that in the illustrated preferred form, the pivot center of each lever, the centers of the links at their ends and the center of the associated eccentric disc are located on one line. This relates to the parts 17, 18, 21 and 23 on the one hand and to the parts 25, 27, Z8 and 30 on the other hand. A connecting or synchronizing rod 31 is pivotally `connected tothe levers 16 and 24 in that its ring-shaped ends 32 and 33 encompass .the eccentric discs 23 and 30 respectively.

2,800,270 Y Y y Thus Vwhen a rocking movement is imparted to the levers in the one direction by plungers 8 and 9 urged outward from their inner dead center positions of Flg. 1 as upon the combustionin the cylinder of an internal combustion engine, both the plungers 12 and 13 willrbe urged towards each other to compress a charge therebetween. Simultaneously, theplunger portions and 171 in cylinder extensions 4 and 5, respectively kwill perform suction strokes whereas plunger portions 14 and 15 will accomplish compression strokes in the cylinder extensions 6 and 7, respectively. When, thereafter, combustion occurs in the cylinder 2 `to urge plungers 8 and 9 apart, the levers 16 and 24 will be rocked in the opposite direction, so thatall the plungers will return to their original positions of Fig. l. The connecting rod 31 ensures the exact synchronization of the movement of the plungers in opposite directions, so that all the plungersv reach their dead centers at the sameV time. VThis is attained `owing to the fact that both eccentrics swing towards the same side whereas the levers rock in opposite directions. It will be noticed that all the movable parts are positively connected whereby the occurrence of knocking due to any lost motion is avoided and furthermore, that ythe masses of the rocking elements can be relatively very small thereby allowing a high speed of operation.

The modification illustrated in Fig. 2, diiersi/rorn that of Fig. l merely in the manner in which the two rocking levers are connected to each other. levers 116 and 124 are pivoted at 117 and 125V in the same manner as the levers 16 and 24. Pins 123 and 130 are secured to the levers 116 and 124, respectively, and a connecting rod 131 is pivotally connected to the pins. The location of Vthe pins in relation to the associated lever journals is similarto the location of the centers of the eccentric discs hereinbefore described with respect to Fig. l.V In other Words, pin 123 is arranged between the center line cz-a and cylinder 2 whereas pin 130 is between the center line a-a and cylinder 3. Furthermore, the centers of the Aparts 117, 123, 118 and 121 are in line, and also the centers of the parts 125, 130, 126 and 128. In all other respects the embodiment of Fig. 2 is similar to and operates in the same manner as the embodiment of Fig. 1.

In many instances, it is advisable to usea synchronizing rod which is adjustable as to its length. For this purpose, a synchronizing rod as shown in Fig. 3 and in general denoted by 231 may be applied instead of the rod 31 in Fig. l. Rod 231 comprises two similar parts each having a ring-shaped head 40 tting the eccentric discs 2,3 and respectively, of Fig. l, a shank portion 41 and a flanged foot portion 42. The foot portions are secured to each other by bolts 43 and a distancepiece 44 or several of such pieces of suitable thickness may be inter-positioned between the foot portions to adjust the total length ofthe rod as desired in accordance with any required tolerances in the assembly of the device. In a similar or any other suitable manner the synchronizing rod 131 of the embodiment of Fig. 2 may be made adjustable.

It will be apparent to those skilled in the art that my invention illustrated and described with reference toa machine assembly comprising .two open ended stepped cylinders is equally well applicable to other machines where the steps are omitted and the cylinders and pistons are of uniform diameter. It will be also apparent that many other alterations and modifications of the structure illustrated and described are possible without departure from 4the essence andspirit of ythe invention which for that reason shall not be limited but by the scope ofthe appended claims.

I claim: l

l. In a machine including two cylinders spaced from .and parallel to each other and two pistons or plungers in each cylinder operative in opposite directions, a driving gear comprising two two-armedrocking levers pivoted to a stationary part of said machine in a plane between and The rocking parallel to said cylinders near the ends of said cylinders, respectively, said four arms being adjacent to said four pistons or plungers, respectively, a link for each arm and being pivotally connected thereto and to said adjacent piston or plunger, and a connecting rod pivotally connected with its ends to said levers eccentrically with respect to the lever pivots so as to ensure simultaneous rocking of said levers in opposite directions, said rod extending wholly within the space between the cylinders and being connected to the levers at locations spaced inwardly substantial distances from the connections of the lever arms to said links.

2. In a machine including two cylinders spaced from and parallel to each other and two pistons, or plungers vin each cylinder operative in opposite directions, a driving gear comprising two two-armed rocking levers pivoted to a stationary part of said machine in a plane between and parallel to said cylinders near-the ends of said cylindersrespectively, saidrfour lever arms being adjacent to said four pistons or plungers, respectively, a link for each arm and pivotally connected thereto and to said adjacent piston or plunger, and a connecting rod pivotally connected with one of its ends to one of said levers at a rst point distanced from the lever pivot on one side of said plane, and pivotally connected with its other-end to said other lever at a second point distanced from said other lever pivot on the otherside of said plane, said rod extending wholly in the space between the cylinders and the connections of the rod to the levers being closer to the lever pivots than are the pivotal connections of the links to the levers. Y

3. A device as claimed in claim 2 wherein the connecting line between the pivot center of said one lever vand said first point is parallel to the connecting line of the pivot center of said other lever and said second point when all pistons or plungers are in their middle positions equally spaced from their dead centers.

4. A device as claimed in claim 2, said connecting rod including two equalrparts andmeans to connect said two parts to each other and to adjust the total length of said connecting rod.

5. A device as claimed in claim 2, said connecting rod comprising two equal parts, each part including a head pivotally connected to one of said levers and a flangelike foot, at least onel distance piece between said feet of said parts, and bolts securing said feet to each other with said distance piece therebetween.

6. Ay drive as claimed in claim 2, each lever including an eccentric disc having its center spaced from the lever pivot, the center of one disc being located on one side of said plane and the center ofthe other disc being located on the other side of said plane, the ends of said connecting rod being ring-shaped and encompassing said discs, respectively.

7. In a machine includingV two cylinders spaced from and parallel to each other, two pistons or plungers in each cylinder operative in opposite directions and a piston rod pivotally connected to each piston or plunger and projecting from the adjacent open cylinder and, a driving gear comprising two two-armed rocking levers pivoted to a'stationary part fof said machine in a plane between and parallel to said cylinders near the ends of said cylinders, respectively, link pins at the ends of the arms of said leversand pivotally connected to the projecting ends of said piston rods, respectively, whereby each lever is pivotally connected to one piston or plunger of each cylinder, and a connecting rod extending wholly in the space between the cylinders and pivotally connected with one of its ends to one of said levers at a point in the space between the cylinders located between the lever pivot and one ofvsaid cylinders, the rod being pivotally connected with its other end to said other lever at a point in the space between the cylinders located between the lever pivot and said other cylinder, wherein on each lever the centers of the pivot, of the link pins and of the pivot j pont of said connecting rod are located in one line.

8. A machine of the type described comprising two cylinders spaced from and parallel to each other, two pistons or plungers in each cylinder operative in opposite directions, -two two-armed rocking levers pivoted-to a stationary part of said machine in a iii-st center plane parallel to and between said cylinders and equally distanced from a second center plane at right angles to the axes and equally spaced from the ends of said cylinders, a piston rod for each piston or plunger and pivotally connected thereto, one arm of each lever being pivotally connected to said piston rod of one of the pistons or plungers of one cylinder and the other arm of each lever being pivotally connected to said piston rod of one of the pistons or plungers of the other cylinder, and a connecting rod extending wholly in the space between the cylinders, the rod being pivotally connected with one of its ends to one of said levers at a point in the space between the cylinders disposed between the lever pivot and the axis of one of said cylinders and being pivotally connected to the other lever at a point in said space between the' pivot point of said last named lever and the axis of said other cylinder, the points of said levers to which said connecting rod is connected being equally spaced from the adjacent lever pivots of the respective levers and being equally spaced from the secondcenter plane when all said pistons or plungers are in their middle positions between' their dead centers.

References Cited in the file of this patent UNITED STATES PATENTS 1,419,159 McKechnie June 13, 1922 2,027,877 Pescara Jan. 14, 1936 2,115,921 Steiner May 3, 1938 2,139,425 Steiner Q Dec. 6, 1938 FOREIGN PATENTS 698,312 Germany Nov. 7, 1940 872,099 France Dec. 6, 1938 

